LONDON, England (CNN) -- A Russian naval ship rescued a Dutch container vessel under attack by suspected Somali pirates in the Gulf of Aden, the head of the International Maritime Bureau said Wednesday.

The Liberian-flagged oil tanker Sirius Star was recently released by pirates off Somalia.

Two or three pirate speedboats were chasing the Dutch ship, with the goal of boarding it, when the Russians intervened, said Capt. Pottengal Mukundan, director of the International Maritime Bureau in London.

He said the pirates fired two rocket-propelled grenades at the Dutch ship, but no injuries were reported.

The incident occurred about midday Tuesday.

The Russians chased one of the speedboats but the pirates got away, Mukundan said. He said he did not know where the Dutch ship was headed.

The troubling rise in Somali piracy has led the United Nations to step up efforts to tackle the crime.

The first U.N. group to address piracy met Wednesday in New York.

Mark Kimmitt, U.S. assistant secretary of state for political-military affairs chaired the "contact group" of two dozen nations and five multi-national organizations.

He said the group was formed to "establish a counter-piracy coordination mechanism," and the members believe more can be done to halt piracy.

Still, Kimmitt noted that less than one percent of manifests off the Somali coast are attacked by pirates and only 50 percent of those have crew and passengers taken hostage.

The U.N. Security Council adopted a resolution in December expanding counter-piracy measures off the Horn of Africa, including a stipulation that allows national and regional military forces to chase pirates onshore in Somalia when in "hot pursuit."